The invention relates to refuse incinerators.
A known refuse incinerator, described in Applicant's Swiss Patent No. 540,463, comprises a grate surmounted by an enclosed generally vertical combustion chamber terminating with a chimney. In its lower part, the combustion chamber has at least one primary air inlet and at least one secondary air inlet. Means, in the form of pipes, are provided for delivering primary air at several levels into the lower part of the combustion chamber and for delivering preheated secondary air at several levels into the upper part of the combustion chamber. The primary air thus passes through and promotes the burning of refuse piled in the combustion chamber, whereas the secondary air serves to promote combustion of the gases produced by combustion of the refuse.
Such incinerators have been found to give a very satisfactory result for the incineration of dry refuse, or only slightly damp refuse. However, the performance with household refuse having a water content of 60 to 70% by weight has been unsatisfactory, This is because the quantity of heat required to evaporate the moisture is so great that it reduces the temperature of the combustion gases whereby the draught in the chimney becomes insufficient to maintain self-combustion of the refuse. Moreover, a greater quantity of primary air is required to ensure combustion, and the non-combustible nitrogen of this air contributes to cooling of the refuse and the combustion gases. As a result, the combustion is incomplete and smelly, polluting gases with a high carbon monoxide content are given off. To satisfactorily burn such household refuse, it has thus been necessary to furnish the incinerators with expedients such as auxiliary burners and mechanical ventilation devices.
An aim of the invention is to provide an incinerator of the type mentioned above in which humid household refuse can be satisfatorily incinerated by self-combustion without a need for auxiliary burners.